Synthesis of anacardic acids in seeds of Ginkgo biloba.

Anacardic (6-alkylsalicylic) acids and common lipids are efficiently synthesized by immature seeds of Ginkgo biloba. The seeds were incubated with 14C-labeled acetic, malonic and palmitoleic acids, glucose, and other potential precursors. Levels of 14C in common lipids and in anacardic acids, and the distribution of 14C in anacardic acids were determined. The results show that the salicylic moiety is synthesized by a polyketide pathway via malonic acid. The chain moiety for anacardic acid synthesis is in a different state of activation and/or site than chains that are used for synthesis of the common lipids. Labeled shikimic acid did not contribute 14C to anacardic acids, nor to other lipids, and palmitoleic acid was incorporated only into common lipids.